World No. 1 Rory McIlroy is focused on becoming a better player in 2013 rather than retaining his place at the summit of the world rankings.

The Northern Irishman, who won the US PGA Championship this year while jostling for the No. 1 spot with Luke Donald, admitted that the majors remain his priority but believes that if he can tighten up his game, the results and rankings will take care of themselves.

"I've always said I want to try and keep improving every year," McIlroy told Sky Sports News. "In the five years that I've been a pro I've improved every year and I just want to try and keep that progression going.

"Majors are definitely the main thing," he added when asked about his goals for next season, before revealing his desire "to keep getting better as a player, improve little areas in my game which I feel like I can improve. If I do that then the tournament wins and the major wins will come."

McIlroy emulated Donald's twin 2011 triumphs in the European Tour Order of Merit and PGA Tour money list this season to finish the season as world No. 1, but admits that life at the top is proving harder than he imagined.

"It's a nice achievement when you get there, but I've found out that keeping that ranking is tougher than getting there," McIlroy continued.

"There's a lot of good players around - Luke [Donald] won last week to move back up to No. 2 - but I've got a little bit of belief at the minute and I want to keep trying to play well and build as big a lead as possible."